Water cooling method for medium-heat lining concrete based on the age of maximum internal and external temperature difference

Abstract

The invention provides a water cooling method for medium-heat lining concrete based on the age of the maximum internal and external temperature difference, which is characterized in that it includes: step 1. collecting data for temperature control of cement concrete in the lining structure; The age of maximum internal and external temperature difference of cement concrete d Δtm =‑0.66×H+0.0004×C‑0.0088×T 0 ‑0.0068×T g +5.02, H is the thickness of hot cement concrete in the lining structure; C is the strength grade of hot cement concrete in the lining structure; T 0 is the pouring temperature of hot cement concrete in the lining structure; T g is the equivalent water temperature value of water cooling, T g =35‑T w ,T w Cooling water temperature for passing water, step 3. Based on d Δtm Determine the water cooling time d j ; Step 4. According to the water cooling time d j Further optimize the water cooling measures of the hot concrete in the lining, and realize the temperature cracks scientifically and reasonably.

Description

technical field

[0001] The invention belongs to the technical field of concrete temperature control and anti-cracking, and in particular relates to a water-through-cooling method for medium-heat lining concrete based on the age of the maximum internal-surface temperature difference. Background technique

[0002] Lining is a structure widely used in civil engineering. Lining concrete will heat up due to the heat of hydration of cement and other cementitious materials, resulting in high internal temperature. For example, the highest temperature inside the lining concrete of the water delivery tunnel in the permanent ship lock of the Three Gorges Water Conservancy Project reaches nearly 60°C, and the lining concrete of the water delivery tunnel of Xiaolangdi Hydropower Station The highest internal temperature reached more than 70°C. The thickness of the lining structure is small, and most of them have high strength (for example, the strength of the spillway tunnel of a large h...

Examples

Embodiment 1

[0041] 1.0m thick (F2 type) lining

[0042] Taking the 1.0m thick (F2 type) lining as an example, the finite element method is used for simulation calculation. The calculation conditions are: start pouring on July 1, the pouring temperature is 27°C, no water cooling temperature control measures are taken, and the side wall adopts C 90 40 normal concrete, the top arch adopts C 25 For pumping concrete, only the side walls and the top arch are studied, and the base plate pouring is not considered. The formwork is removed after 3 days of pouring. The interval between side wall and top arch pouring is 31 days, and the length of the joint is 9m.

[0043] The maximum temperature, the maximum internal surface temperature difference and the occurrence time of the typical parts of the 1.0m thick (F2 type) lined concrete side wall are shown in Table 2 below, and the temperature duration curve is shown in Figure 5 .

[0044] Table 2 The maximum temperature and appearance time of repr...

Embodiment 2

[0058] The lining structure of the Xiluodu flood discharge tunnel is 0.8m and 1.5m thick with medium-heat cement concrete

[0059] In order to analyze the applicability of formula 1 for lining thickness and water cooling conditions, for Figure 4 For the section of the lining structure, keep the section size after lining unchanged and only change the thickness of the lining to 0.8m and 1.5m. First, use the finite element method to simulate and calculate, and then use formula 1 to calculate the maximum internal surface temperature difference occurrence age d Δtm Calculation.

[0060] Finite element simulation calculation, the calculation scheme in the case of water cooling is as follows: pouring starts on July 1 in summer, the bottom plate and side and roof arches are poured separately, and the pouring interval is 31 days; the pouring temperature is 18°C, the distance between water pipes is 1.0m, and the water Cool in water at 15°C for 15 days, remove the mold after 3 days, a...

technical field

[0001] The invention belongs to the technical field of concrete temperature control and anti-cracking, and in particular relates to a water-through-cooling method for medium-heat lining concrete based on the age of the maximum internal-surface temperature difference. Background technique

[0002] Lining is a structure widely used in civil engineering. Lining concrete will heat up due to the heat of hydration of cement and other cementitious materials, resulting in high internal temperature. For example, the highest temperature inside the lining concrete of the water delivery tunnel in the permanent ship lock of the Three Gorges Water Conservancy Project reaches nearly 60°C, and the lining concrete of the water delivery tunnel of Xiaolangdi Hydropower Station The highest internal temperature reached more than 70°C. The thickness of the lining structure is small, and most of them have high strength (for example, the strength of the spillway tunnel of a large h...

Examples

Embodiment 1

[0041] 1.0m thick (F2 type) lining

[0042] Taking the 1.0m thick (F2 type) lining as an example, the finite element method is used for simulation calculation. The calculation conditions are: start pouring on July 1, the pouring temperature is 27°C, no water cooling temperature control measures are taken, and the side wall adopts C 90 40 normal concrete, the top arch adopts C 25 For pumping concrete, only the side walls and the top arch are studied, and the base plate pouring is not considered. The formwork is removed after 3 days of pouring. The interval between side wall and top arch pouring is 31 days, and the length of the joint is 9m.

[0043] The maximum temperature, the maximum internal surface temperature difference and the occurrence time of the typical parts of the 1.0m thick (F2 type) lined concrete side wall are shown in Table 2 below, and the temperature duration curve is shown in Figure 5 .

[0044] Table 2 The maximum temperature and appearance time of repr...

Embodiment 2

[0058] The lining structure of the Xiluodu flood discharge tunnel is 0.8m and 1.5m thick with medium-heat cement concrete

[0059] In order to analyze the applicability of formula 1 for lining thickness and water cooling conditions, for Figure 4 For the section of the lining structure, keep the section size after lining unchanged and only change the thickness of the lining to 0.8m and 1.5m. First, use the finite element method to simulate and calculate, and then use formula 1 to calculate the maximum internal surface temperature difference occurrence age d Δtm Calculation.

[0060] Finite element simulation calculation, the calculation scheme in the case of water cooling is as follows: pouring starts on July 1 in summer, the bottom plate and side and roof arches are poured separately, and the pouring interval is 31 days; the pouring temperature is 18°C, the distance between water pipes is 1.0m, and the water Cool in water at 15°C for 15 days, remove the mold after 3 days, a...

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